Role: in the mounted armor layer process, prevent the shield was bruised by armored layer; laying operation, can resist the invasion of external corrosion, metal sheath (jacket) corrosive medium of contact with the outside world, extending the service life of the cable.

(2) armored layer

Role: prevent the cable during the installation process or mechanical damage during the operation were possible in the process, to ensure the integrity shield, and can withstand a certain amount of force.

(3) outer layer

The role: is to protect armored layer to prevent armored layer damage during the laying process. Consists of the plastic sheath outside were armored layer by layer can prevent corrosion during operation.

Cable sheath is guaranteed to maintain excellent electrical properties of the cable once the shield damage, cable will fail, could not continue to run, so that the service life of the cable, to a large extent depend on the life of the cable sheath, the life of the cable sheath depends in large part on manufacturing quality of the jacket.